Effect of annealing atmosphere on the contact resistivity, superconductivity, and phase transformation in the Al/BiSrCaCuO system

Journal Article · Sun Dec 01 04:00:00 EST 1991 · Journal of the Electrochemical Society; (United States)

DOI:https://doi.org/10.1149/1.2085480· OSTI ID:5070437

Lin, W T; Kao, H P ^[1]; Fang, Y K ^[2]; Pan, F M ^[3]

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1. Dept. of Materials Engineering, National Cheng Kung Univ., Tainan (TW)
2. Inst. of Electrical and Computer Engineering, National Cheng Kung Univ., Tainan (TW)
3. Materials Research Lab., ITRI, Hsinchu (TW)

This paper reports on the contact resistivity, superconductivity, and phase transformation in the Al/BiSrCaCuO(BSCCO) system annealed in air, argon, and vacuum, respectively. The BSCCO films were deposited by dc sputtering on MgO substrates. For the Al/BSCCO films, capped with gold and annealed at 750{degrees} C in air, the contact resistivity of 7 {times} 10{sup {minus}7} {Omega}-cm{sup 2} at 77 K can be obtained, whereas for the Al/BSCCO films annealed at above 500{degrees} C either in argon or in a vacuum of 6 {times} 10{sup {minus}6} Torr, the contact resistivities show semiconducting behavior due to degraded superconductivity of the BSCCO film. During annealing in argon or a vacuum of 6 {times} 10{sup {minus}6} Torr the melting temperatures of the 2212 phase are about 750 and 675{degrees} C, respectively. These are considerably lower than that in air, 875-895{degrees} C. The 2201 phase is the most stable phase in comparison with the 2212 and Bi{sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} phases during annealing in the oxygen-free atmosphere. The reversible change of the T{sub c} of the BSCCO film has an intimate relationship with the decomposition and recrystallization of the 2212 phase, depending on the annealing atmosphere. Two of the decomposition products of the 2212 phase for the BSCCO film annealed in the oxygen-free atmosphere are identified to be {delta}-Bi{sub 2}O{sub 3} and Cu{sub 2}O. In this study, the phase transformation and reversible change of the T{sub c} for the BSCCO film annealed in various atmospheres can be explained in terms of the desorption and absorption of oxygen in the film.

• OSTI ID: 5070437
• Journal Information: Journal of the Electrochemical Society; (United States), Journal Name: Journal of the Electrochemical Society; (United States) Vol. 138:12; ISSN 0013-4651; ISSN JESOA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360202 -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
360204 -- Ceramics
Cermets
& Refractories-- Physical Properties
360207 -- Ceramics
Cermets
& Refractories-- Superconducting Properties-- (1992-)
665412* -- Superconducting Devices-- (1992-)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANNEALING
ARGON
BISMUTH COMPOUNDS
CONTROL
DESORPTION
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELEMENTS
FILMS
FLUIDS
GASES
HEAT TREATMENTS
NONMETALS
OXYGEN
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
PROCESS CONTROL
RARE GASES
SORPTION
SPUTTERING
STOICHIOMETRY
SUPERCONDUCTING FILMS
SUPERCONDUCTIVITY
TEMPERATURE EFFECTS
THERMODYNAMIC PROPERTIES